module GraphQL::StaticValidation::FragmentTypesExist

def on_fragment_definition(node, _parent)
  if validate_type_exists(node)
    super
  end
end

def on_inline_fragment(node, _parent)
  if validate_type_exists(node)
    super
  end
end

def validate_type_exists(fragment_node)
  if !fragment_node.type
    true
  else
    type_name = fragment_node.type.name
    type = @types.type(type_name)
    if type.nil?
      @all_possible_fragment_type_names ||= begin
        names = []
        context.types.all_types.each do |type|
          if type.kind.fields?
            names << type.graphql_name
          end
        end
        names
      end
      add_error(GraphQL::StaticValidation::FragmentTypesExistError.new(
        "No such type #{type_name}, so it can't be a fragment condition#{context.did_you_mean_suggestion(type_name, @all_possible_fragment_type_names)}",
        nodes: fragment_node,
        type: type_name
      ))
      false
    else
      true
    end
  end
end